A high-profile case of document theft in US history alerts archives to a latent threat.

A letter from Benjamin Franklin dated April 1, 1780. An admission ticket to the gallery for Andrew Johnson’s impeachment trial. A reading copy of Franklin Delano Roosevelt’s 1937 inaugural addresses, with the president’s notations and signature.

These were among the 10,000 stolen documents and objects of cultural heritage discovered in 2011 in the New York City apartment of self-styled presidential historian Barry Landau.